Fix the remaining cases of <prog>_CFLAGS -> <prog>_CPPFLAGS

Building BIND 9 with older version of BIND 9 installed would result in
build failure.  Fix the last two remaining cases where <prog>_CFLAGS was
being used leading to wrong order of the build flags on the command line.

(cherry picked from commit 41a60a0e21)

bin/tools/Makefile.am

@@ -47,7 +47,7 @@ if HAVE_LMDB
 bin_PROGRAMS +=			\
 	named-nzd2nzf
 
-named_nzd2nzf_CFLAGS =		\
+named_nzd2nzf_CPPFLAGS =		\
 	$(AM_CPPFLAGS)		\
 	$(LMDB_CFLAGS)
 

doc/misc/Makefile.am

@@ -55,8 +55,8 @@ MAINTAINERCLEANFILES = $(OPTIONS_FILES)
 
 noinst_PROGRAMS = cfg_test
 
-cfg_test_CFLAGS =			\
-	$(AM_CFLAGS)			\
+cfg_test_CPPFLAGS =			\
+	$(AM_CPPFLAGS)			\
 	$(LIBISC_CFLAGS)		\
 	$(LIBDNS_CFLAGS)		\
 	$(LIBISCCFG_CFLAGS)